single acting

[J_J]

If you are satisfied with a SA cyl, then continue using it.

It does need some weight to make it retract.

I don't believe one can convert a SA cyl to DA.

If you keep adding valves, you will have a spaghetti mix on the area.

If you use stacked valves, you can mix DA spools with SA spools in the stacked valve arrangement.

 

[dfkrug]

I don't believe one can convert a SA cyl to DA.

Well that's nice, but I have done it.

It is much easier than buying a new cyl.

If you look at the piston seal on a SA cyl, it may not be intended to work optimally in both
directions, but it also might be a symmetrical seal. It does not really matter if
the retraction forces are not great, as in this application.

Of course, you can not convert a "displacement cylinder", which is single acting cyl with
the rod diameter equal to the cyl ID.

 

[Young Ed]

If you are satisfied with a SA cyl, then continue using it.

It does need some weight to make it retract.

I don't believe one can convert a SA cyl to DA.

If you keep adding valves, you will have a spaghetti mix on the area.

If you use stacked valves, you can mix DA spools with SA spools in the stacked valve arrangement.

the tipping trailer empty is heavy enough to lower with the current SA cylinder so that is no problem
don't mind having the odd pipe here and there as i am used to that in any case but yes working on it could be confusing but i can live with that

when you say stacked valves do you mean like this?


i would install a 2 valve block like the above of DA valves and then a single SA valve separate for things such as the trailer and lowering and raising SA mowers
Cheers Ed

 

[J_J]

No, that is a monoblock valve , a one piece construction body.

Here is a stacked valve.

4 SPOOL 20 SERIES PRINCE STACK VALVE CLOSED CENTER

You have individual spool sections and an inlet and outlet section.

 

[Young Ed]

ah!
would indeed make things neater with only one feed and one dump line and also it would be cheaper as i wouldn't need so many hoses making up

now i just need to find one in the UK or see how much it is it import one from the US
Cheers Ed

 

[Young Ed]

is this what you call a stacked valve in America?
Bucher hydraulic 2 bank monoblock lever valve 70l/min 1/2"ports HDM18 ZZ001759 | eBay
called a mono block valve in the UK?
would it be possible to have one with 2 double acting valves and one single acting valve all in one block? would this have to be how it was made and not something i could add i'm guessing?
Cheers Ed

 

[Young Ed]

actually scrap what i just posted above, i'm pretty sure that's still not a stacked valve
Cheers Ed

 

[J_J]

Do you absolutely need a SA valve with only one work port.

A DA valve will do the same thing after plugging one p ort.

There are plenty out there.

https://www.google.com/search?q=ces...a=X&ei=Z_NkVNOhK8eogwTgmoOwDg&ved=0CAYQ_AUoAQ

It is just too easy to convert a DA valve spool to SA by plugging one of the work ports, or running the unused workport to tank.

A monoblock valve is one piece construction.

A stacked valve is just that, spool sections stacked together with an input and output, and bolted together..

 

[J_J]

Sounds like you need a three spool DA valve and plug one work port on the third valve to make it a SA spool.

 

[Young Ed]

plugging one work port on a DA, now that sounds like an idea!
or as you say i could run it to the dump line, would just plugging it cause any extra wear to the pump?
is this all i need to plug it, obviously in the right size
Blanking Plug Hydraulic Compression Fittings Part Number - VS-M20X1.5-WD | eBay

also is the dump line under pressure, would i need a check valve on any lines T'ing into the dump line to stop other oil being dumped going up the pipe T'ing into the main dump line, if this makes sense? can do a basic diagram if it helps?
Cheers Ed